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Biomedical subjects

M Loebe

Publications and source records attributed to M Loebe.

At least 73 records · Page 4Linked to original sources

Weaning from mechanical cardiac support in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: Implantation of mechanical cardiac support systems (MCSS) in patients with idiopathic dilated cardiomyopathy (IDC) may improve cardiac function and allow explantation of the device. We report of long-term effects of ventricular unloading on cardiac function, humoral anti-beta1-adrenoceptor autoantibodies (A-beta1-AABs), and myocardial fibrosis. METHODS AND RESULTS: Seventeen patients in New York Heart Association functional class IV with nonischemic IDC received MCSS. All had a cardiac index of < 1.6 L x min(-1) x m(-2) of body surface area, a left ventricular ejection fraction (LVEF) of <16%, and a left ventricular internal diameter in diastole (LVIDd) of >68 mm and tested positive for A-beta1-AABs. Echocardiographic evaluation, serum tests for A-beta1-AABs, and histological assessment of myocardial fibrosis were performed before and after MCSS implantation. The mean support duration was 230+/-201 days. Six patients died, four were transplanted, and two are still on MCSS. Five patients with significant cardiac recovery (mean LVIDd, 54+/-2.3 mm; LVEF, 47+/-3.7%) were weaned after 160 to 794 days and are now device free for 51 to 592 days. A-beta1-AABs disappeared gradually during MCSS without increase after weaning; cardiac function and volume density of fibrosis remained normal. Nine patients' cardiac function hardly improved during ventricular unloading. CONCLUSIONS: Cardiac function can be normalized in selected patients with end-stage IDC by MCSS. The degree of preoperative myocardial fibrosis may be an indicator for outcome; A-beta1-AABs can be used to monitor myocyte recovery. Weaning from MCSS offers an alternative to cardiac transplantation in certain patients.

Adult↗

[Temporary mechanical left heart support. Recovery of heart function in patients with end-stage idiopathic dilated cardiomyopathy].

BACKGROUND: Implantation of a mechanical cardiac support system (MCSS) in patients with idiopathic dilated cardiomyopathy (IDC) may improve cardiac function and allow explantation of the device. Our experience now includes 13 patients who have been "weaned" from MCSS and we report about the overall results of this treatment as well as the effects of ventricular unloading on cardiac function, anti-beta 1-adrenoceptor-autoantibody (A-beta 1-AAB) level and the degree of myocardial fibrosis. METHODS: 13 patients with non-ischemic IDC who had been admitted here in cardiogenic shock (CI < 1.61.min-1.m2, left ventricular ejection fraction [LVEF] < 16% and left ventricular internal diameter in diastole [LVIDd] > 68 mm) and who all tested positive for A-beta 1-AABs were implanted with an uni-(12 patients) or a biventricular (1 patient) mechanical assist device. Echocardiographic evaluation and A-beta 1-AAB-level-monitoring was routinely performed after implantation and explantation of the MCSS and the degree of myocardial fibrosis was assessed at the time of implantation and after explantation. RESULTS: During a mean duration of mechanical support of 236 +/- 201 days (range: 30 to 794 days), LV-EF improved to a mean of 46% and LVIDd decreased to a mean value of 56 mm in these 13 patients. A-beta 1-AABs decreased and disappeared 11.7 weeks after implantation of the device and did not reincrease thereafter. The highly pathologic degree of fibrosis at the time of implantation diminished to normal values about 1 year after explantation. One patient died of anesthesiologic complications and another patient shortly presented with a new episode of cardiac insufficiency 6 months after explantation. He was implanted again with an univentricular assist device was successfully transplanted 3 weeks later. Mean observation period of the remaining 11 patients now amounts to 12.6 +/- 9.77 (range: 3 to 26) months after explantation of the device--as of May, 31, 1997--with a cumulative observation period of 139 patient months. CONCLUSION: Temporary implantation of a MCSS may normalize cardiac function in selected patients with IDC. The striking degree of myocardial fibrosis can reduce to normal values after explantation of the device. A-beta 1-AABs disappear during ventricular unloading and do not increase thereafter. "Weaning" from mechanical device may constitute an alternative treatment to cardiac transplantation in selected patients.

Adult↗

Status of patients presently living 9 to 13 years after orthotopic heart transplantation.

BACKGROUND: Heart transplantation has a dramatic impact on both life expectancy and quality of life in patients with terminal heart failure. The aim of the study was to evaluate psychologic, social, occupational, and somatic status of patients living long-term, 9 to 13 years after orthotopic heart transplantation. PATIENTS AND METHODS: Seventy-seven of 182 patients who received transplants between July 1983 and January 1988 in Hannover (1983-1985; n = 69 patients) and Berlin (1986-1988; n = 113 patients) have survived up to now, 9 to 13 years after transplantation (mean, 10 years 4 months). The patients and their medical records (eg, cardiac catheter studies, echocardiography) were examined to assess their somatic status. Psychologic, social, and occupational status and quality of life data were assessed by combination of self-rating questionnaires (the Short Form Health Survey Questionnaire, Giessener Beschwerdebogen [the Giessen Subjective Complaints List], the Sickness Impact Profile, and the Hospital Anxiety and Depression Scale) and semistructured interviews. RESULTS: Ninety-one percent of the patients were in New York Heart Association functional class I (70%) or II (21%). The results of the psychologic investigation revealed a definite impact of the side effects of chronic immunosuppression; however, overall, the quality of life rating was within the normal range. Sixty-seven (86%) patients were married, 51 (66%) patients were retired, 17 (22%) worked full-time or part-time, and 9 (12%) were housewife or houseman. Four male patients have fathered five healthy children 1 to 10 years after the transplantation. More than 75% of the patients had normal systolic ventricular function (mean left ventricular ejection fraction, 0.63). Coronary angiograms were normal or with minor wall irregularities in 86% (n = 66 patients), and revealed severe obstructions in 14% (n = 11). Normal function of all valves was found in one-third of the patients, tricuspid valve incompetence was not found or was insignificant in 87% (n = 67 patients) and severe in 8% (n = 10). Six patients had undergone tricuspid valve replacement, invariably for structural valve defects attributable to biopsy injuries. Fifty-eight patients (75%) exhibited various degrees of compensated renal insufficiency, 7 of them were on chronic hemodialysis, and 2 patients have undergone kidney transplantation. Hepatic function was normal in 68% (n = 52) of the patients, and 1 patient has developed liver cirrhosis. Osteoporosis was diagnosed of the discrete form in 7 (9%) and of a significant degree in 24 patients (31%); 38.5% (n = 30) complained of symptoms of polyneuropathy. CONCLUSIONS: The patients surviving 9 to 13 years after orthotopic heart transplantation are mostly in good physical status, the quality of life is comparable to the general population, and only a few of them have significantly limited in their life style. They do show the substantial chronic side effects of long-term immunosuppression, remaining treatment-dependent for a lifetime.

Adolescent↗

Circulatory support with paracorporeal pneumatic ventricular assist device (VAD) in infants and children.

OBJECTIVE: The feasibility and efficacy of the pneumatic 'Berlin Heart' ventricular assist device (VAD) were evaluated in 14 pediatric patients with profound cardiogenic shock refractory to conventional therapy. METHODS: There were two patient groups. Eleven patients, aged 2 weeks 15 years and weighing 3.2-52 kg received a left ventricular assist device or a biventricular assist device as a bridge to cardiac transplantation (bridge group). Nine of them had liver, kidney, or lung dysfunction before device implantation. Three patients were supported with a biventricular assist device for myocardial recovery (recovery group): a 6-month-old girl for postcardiotomy shock, a 10-month-old girl for allograft failure after cardiac transplantation, and a 4-year-old boy with acute myocarditis. RESULTS: In the bridge group, eight patients were transplanted after a bridge duration of 6-98 days (mean, 32 days) with five long-term survivors. Organ functions were normalized during bridging in all of the transplant recipients. In the recovery group, the first patient was removed from support after 2 days because of irreversible brain damage. The second patient was weaned from biventricular support after 8 days, but suffered from recurrent allograft failure. The third patient received biventricular support for 21 days followed by extracorporeal membrane oxygenation and was subsequently discharged from the hospital. CONCLUSIONS: The 'Berlin Heart' VAD can keep selected infants and children with life-threatening heart failure for weeks or months.

Adolescent↗

Angiotensin II-induced leukocyte adhesion on human coronary endothelial cells is mediated by E-selectin.

Clinical data suggest a link between the activation of the renin-angiotensin system and cardiovascular ischemic events. Leukocyte accumulation in the vessel wall is a hallmark of early atherosclerosis and plaque progression. E-Selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) are adhesion molecules participating in mediating interactions between leukocytes and endothelial cells and have been found to be expressed in athero-sclerotic plaques. We investigated whether angiotensin II, the effector of the renin-angiotensin system, influences the endothelial expression of E-selectin, VCAM-1, and ICAM-1. In coronary endothelial cells derived from explanted human hearts, angiotensin II (10(-11) to 10(-5) mol/L) induced a concentration-dependent increase in E-selectin expression. The effect was measured by cell ELISA and duplex reverse-transcription polymerase chain reaction (RT-PCR) and reached its maximum at 10(-7) mol/L. Angiotensin II induced only a small increase in E-selectin expression in cardiac microvascular endothelial cells. VCAM-1 and ICAM-1 were not affected by angiotensin II stimulation. In addition, the effect of angiotensin II-induced E-selectin expression on leukocyte adhesion was quantified under flow conditions. Angiotensin II (10(-7) mol/L) increased leukocyte adhesion significantly to 67% of the maximal effect by tumor necrosis factor-alpha at a wall shear stress of 2 dyne/cm2. This adhesion was found to be E-selectin dependent, as demonstrated by blocking antibodies. The AT1-receptor antagonist DUP 753 significantly reduced E-selectin-dependent adhesion, whereas the AT2-receptor antagonist PD 123177 had no inhibitory effect. In addition, only AT1-receptor, but not AT2-receptor, mRNA could be detected by RT-PCR in coronary endothelial cells. Therefore, it is suggested that AT1 receptors mediate the effects of angiotensin II on E-selectin expression and leukocyte adhesion on coronary endothelial cells.

Angiotensin II↗

Long-term mechanical circulatory support as a bridge to transplantation, for recovery from cardiomyopathy, and for permanent replacement.

Since 1988, 295 patients have undergone MCS at the German Heart Institute Berlin; 246 received biventricular support with the extracorporeal pneumatically-driven Berlin Heart Assist Device, 49 received left ventricular support with implantable assist devices (33 Novacor, 16 TCI). Longer waiting periods for heart transplantation has caused the mean duration of MCS to increase from 12 days in 1988 to 76 days in 1994. Of the 24 patients who underwent MCS for more than 90 days, nine were implanted with a biventricular device, 12 with a Novacor device, and 15 with a TCI device. Eight patients with uni-ventricular devices remain on support after 200 days (range 203-600 days). Six of the Novacor patients could be discharged to a nursing home or to their own residences. One patient still on NC support after more than 600 days currently resides at his home and has regained normal physical activity. Minor pocket infections occurred in two TCI and four Novacor patients; one patient died of sepsis. A total of four patients could be weaned from LVAD after 160-347 days of MCS. An initial high level of beta1 receptor antibodies disappeared completely during left ventricular support. This decline in auto-antibodies was paralleled by a dramatic improvement in cardiac function. LVEF remained unchanged up to 6 months after explantation. Long-term mechanical support has become a reality. Heart transplantation after prolonged MCS yields results comparable to primary HTx. Some patients exhibit immunological changes and a dramatic improvement in ventricular function under long-term MCS and can be weaned with extremely satisfying results.

Adolescent↗

Successful mechanical circulatory support for more than two years with a left ventricular assist device in a patient with dilated cardiomyopathy.

A 36-year-old man with dilated cardiomyopathy was supported with a left ventricular assist device for 795 days. During this support time gradual functional recovery was noted. The patient tolerated the device well, enjoyed a good quality of life, and experienced no technical device-related problems. When a suitable donor heart became available, the device was switched off, and native ventricular function was assessed. This was judged to be acceptable, and the left ventricular assist device was successfully explanted. Postexplantation function remained acceptable and improved over the following days. The patient was discharged on the twentieth postoperative day and remains well.

Adult↗

[Surgical therapy of chronic atrial fibrillation with the "Cox/Maze-III-operation"].

UNLABELLED: We examined the results of simultaneous surgical treatment of chronic atrial fibrillation using a Cox/Maze III operation during mitral valve surgery (n = 12), atrial secundum defect closure (n = 1), combined operation (mitral valve and atrial secundum; n = 1) and thrombectomy from the left atrium (n = 1). Mean preoperative atrial fibrillation was 5.1 years (range 0.5-12 years). In the mean follow-up period of 13.1 months (1-24 months), 14 patients (93%) had sinus rhythm. CONCLUSION: (1) The surgical treatment of chronic atrial fibrillation using a Cox/Maze III operation can be performed without increased perioperative or postoperative risks; (2) Cox/Maze III operation represents an effective surgical treatment of chronic atrial fibrillation.

Aged↗

Heart transplantation: a single-center experience.

BACKGROUND: The success of heart transplantation led to the extension of the criteria for both recipients and donors. The aim of the study was to evaluate the experience with this therapeutic approach for end-stage heart failure at a single center. METHODS: Between April 1986 and January 1996, 1,413 patients were accepted as candidates for heart transplantation. Ventricular assist devices were used as a bridge to transplantation in 173 patients (biventricular assist device in 141 patients and left ventricular assist device in 32 patients). The longest duration of support was 572 days (average, 46 days). RESULTS: Of the 1,413 patients, 891 underwent heart transplantation (65 children/adolescents and 826 adults; 522 (36%) patients died awaiting a donor heart. The average time spent on the waiting list was 107 days. The average recipient age was 44 years, and the age of donors was extended up to 69 years. Eighty-three patients with ventricular assist devices (48%) subsequently underwent heart transplantation. Twenty-five patients (2.7%) underwent retransplantation. The 30-day mortality rate was 14%, and the overall actual survival at 1, 5, and 10 years was 80%, 59%, and 50%, respectively. Ninety-four percent of patients were in New York Heart Association functional class I or II at 1 year, and 44% returned to work after transplantation. CONCLUSIONS: Despite the broadening of the selection criteria for both recipients and donors, heart transplantation remains an effective treatment for end-stage heart failure. Nevertheless, this therapeutic approach is severely limited by a considerable disparity between the need and availability of donor organs.

Adolescent↗

Extracorporeal membrane oxygenation as a bridge to cardiac transplantation in children.

The feasibility and efficacy of extracorporeal membrane oxygenation (ECMO) as a bridge to cardiac transplantation was examined in 6 pediatric patients who suffered irreversible myocardial failure after undergoing surgery for congenital heart defects. The mean time of ECMO support was 260.5 h, range 101-402 h. Three patients underwent transplantation, 2 of whom are long-term survivors. Progressive hypotension as a result of capillary leak syndrome precluded further ECMO support in the other 3 patients. Overall, 2 of the 6 patients survived. Major complications were encountered in 4 patients including bleeding in 2, a seizure in 1, and renal failure in 3, 2 of whom recovered renal function after transplantation. Infection did not occur in any of the 6 patients. Exchanging ECMO components was performed with no difficulties; these exchanges included a centrifugal pump once for 3 patients and a membrane oxygenator once for 2 patients. Our results indicate that ECMO can safely keep critically ill pediatric transplant candidates alive for more than 1 week with a low incidence of multiple organ failure.

Adolescent↗

[Adults with congenital heart defects--clinical spectrum and surgical management].

Two hundred adults who underwent surgery for congenital heart disease at our institution within a four year period were the basis for this report. Clinical data was obtained, i.e. demographic details, past medical history, physical findings, EKGs, echocardiograms, catheterization and angiography material as well as the New York Heart Association (NYHA) class. Intraoperative findings, perioperative management, complications and morbidity and mortality were assessed. After discharge the patients were followed on an outpatient basis. Again the clinical findings, laboratory results and NYHA class were recorded. Age ranged from 16 to 75 years (mean = 38). There were 114 females and 86 males. 178 patients had primary surgical correction, 18 were reoperated after prior correction and 4 underwent palliation. Eighty-three percent of the patients were symptomatic preoperatively. Seventeen percent were diagnosed per chance, for example by a preemployment physical examination, without a prior history of heart disease. The patients were grouped according to related diagnoses (Table 1). Among the 130 patients with left to right shunts, 112 had an atrial septal defect, 7 a ventricular septal defect, 5 a persistent ductus arteriosus, and 6 partial anomalous pulmonary venous return. Atrial flutter or fibrillation occurred in approximately 10% of all patients with atrial septal defects. It was terminated either by rapid overdrive pacing or DC cardioversion. Postoperatively the patients with pulmonary hypertension were monitored invasively with arterial lines and thermodilution catheters. Therapy consisted of alkalization, hyperventilation and sedation. There was only one postoperative death in this patient group due to marked pulmonary hypertension (1/130 = 0.8%). Nineteen adults had obstruction to right or left ventricular outflow. Surgery included valvotomy, infundibulectomy and valve replacement by homograft or mechanical valve. One patient with multiple previous surgeries expired due to bleeding (3%). Thirteen patients had coarctation. All of them were hypertensive, some on medication. Surgery consisted of aortic patchplasty or interposition of a graft. There was no mortality. Perioperative antihypertensive therapy was necessary in most patients and consisted of nifedipin, nitroprussid or propanolol intravenously. Upon follow up 11 patients became normotensive, 8 of these without the need for medication. Fifteen cyanotic patients underwent 11 corrective and 4 shunt procedures (3 with tricuspid atresia, 10 with Tetralogy of Fallot and 2 with complex cyanotic heart disease. Three died due to low cardiac output or dysrhythmias (20%). The survivors improved their clinical status markedly. Seven adults with Ebstein's disease had valve reconstruction and/or ASD closure. Five had recurrent supraventricular tachycardia, 2 paradoxical emboli with neurological symptoms and 4 out of 7 had decreased exercise tolerance. One patient died postoperatively because of dysrhythmias (14%). Sixteen patients had a variety of defects, i.e. status post Rastelli operation and conduit obstruction, status post Tetralogy of Fallot with pulmonary valvar disease, corrected transposition with left AV valve insufficiency, congenital mitral valve disease and double aortic arch, no deaths. The overall operative mortality was 6/200 = 3%. the late mortality was 4/200 = 2%. The morbidity included 7 reoperations due to bleeding. Five patients needed short-term hemodialysis. One patient developed hemiplegia and two patients had permanent decrease of their left ventricular function. The mean length of follow up was 21 months. The clinical status improved from a NYHA class mean of 2.1 +/- 0.9 to 1.2 +/- 0.45 (p < 0.001). In Germany significant numbers of adults with operated and unoperated congenital heart disease do exist. Detection of these patients can be difficult due to inconspicuous murmurs or stable clinical status.

Adolescent↗

Successful extracorporeal circulatory support after aortic reimplantation of anomalous left coronary artery.

The development of severe heart failure is the main cause of postoperative mortality after the surgical treatment of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA). Two patients with ALCAPA who developed low cardiac output and could not be weaned from cardiopulmonary bypass (CPB) after aortic reimplantation of the anomalous left coronary artery were successfully treated with a centrifugal left ventricular assist device (LVAD) and extracorporeal membrane oxygenation (ECMO). The circulation of a 10-month-old infant with severe left ventricular dysfunction was supported 192 h postoperatively with a LVAD and a 9-year-old boy with severe right ventricular failure received ECMO support for 99 h following surgery. Both patients survived and, 4 and 9 months after surgery, are asymptomatic and have normal ventricular function. If CPB (up to 3 h) is not effective in improving ventricular function after surgery for ALCAPA, ECMO or LVAD must be used since myocardial recovery in these patients can occur only after prolonged extracorporeal circulatory support.

Cardiopulmonary Bypass↗

Anomalous origin of the left coronary artery from the pulmonary artery. Early results with direct aortic reimplantation.

Between January 1991 and June 1993, eleven children with anomalous origin of the left coronary artery from the pulmonary artery underwent direct aortic reimplantation of the left coronary artery at the German Heart Institute Berlin. The patients' ages ranged from 2.5 months to 10.5 years; six were infants. Three infants were intubated and their lungs ventilated before the operation, and one was resuscitated 2 days before the operation. The electrocardiograms of eight patients indicated deep Q waves. All but three of these patients had insufficient collaterals between the right and left coronary arteries. The entire group exhibited reduced left ventricular ejection fraction (minimum 15%) including mitral valve incompetence, which was moderate in six patients and severe in three. All six infants underwent emergency operations, and the remaining children, who were older, underwent elective operations involving moderate hypothermic perfusion and cold crystalloid cardioplegia. Aortic cross-clamping time ranged from 22 to 79 minutes (mean 54 minutes). A two-coronary artery system was established in all patients by direct reimplantation of the anomalous left coronary artery into the ascending aorta. Three patients who also exhibited severe mitral valve incompetence underwent modified Kay mitral valve annuloplasty. A delayed sternal closure procedure (closure performed 1 to 10 days after the operation) was used on eight patients. A 10-month-old patient was successfully treated after the operation with a centrifugal left heart assist device and a 9-year-old patient received extracorporeal membrane oxygenation because of severe heart failure. No postoperative deaths occurred. Left ventricular end-diastolic volume decreased dramatically after the operation and returned to near normal values 1 to 9 months postoperatively. At the same time, the preoperatively depressed left ventricular ejection fraction returned to normal and mitral valve incompetence decreased or vanished in eight patients. Color Doppler echocardiograms (eleven patients) and coronary angiograms (three patients) indicated that the reimplanted left coronary artery was patent in all eleven patients during the follow-up period. Reimplantation of the left coronary artery into the ascending aorta is an effective method of establishing a two-coronary artery system in children with anomalous origin of the left coronary artery from the pulmonary artery. Mitral valve annuloplasty is recommended for patients who also have severe mitral valve incompetence. Prolonged assisted circulation must be used in cases of severe postoperative heart failure.

Aorta↗

[Treatment of low cardiac output syndrome in newborn infants and children].

A refractory low-cardiac-output syndrome is, in pediatric patients, most often due to impaired myocardial function after corrective surgery in congenital heart disease. Therapy has to focus on postoperative adaptation, which usually takes place within a few days. We report on three therapeutic strategies to "bridge" this phase of postoperative adaptation. Improving the contractile state of the myocardium using enoximone was attempted in 16 neonates with low-cardiac-output syndrome refractory to catecholamines (Dosage: loading-dose 1 mg/kg in 10 min intravenously, followed by an infusion of 10 mcg/kg/min). In 12/16 neonates cardiac index increased by more than 20% ("responder"), while in 4/16 neonates cardiac index remained unchanged ("non-responder"). All non-responders succumbed due to refractory low-cardiac-output syndrome, while only one responder died in low-cardiac-output syndrome. Hemodynamically, enoximone resulted in an increase of cardiac index and stroke volume (p < 0.003), a reduced systemic vascular resistance (p < 0.0022), and reduced right and left atrial pressures (p < 0.003). Heart rate and mean arterial pressure remained unchanged. No rhythm disturbances were observed. Another therapeutic approach to postoperative low-cardiac-output syndrome is atrial decompression by creating an atrial septal defect. Due to the possibility of later transcatheter closure of these defects, the acceptance for the intraoperative creation of an atrial communication to decompress the right or left atrium is increased. The defect size is critical and should be below 9 mm, so that the Rashkind-PDA-Occluder can be used for later transcatheter closure. We performed such a "surgical-interventional" decompression in 18 patients (age: 2 weeks to 7 years). In six patients the atrial defect was created because of an underdeveloped left ventricle (body weight 2.9-9.2 kg), in 12 patients for right atrial decompression during a total cavopulmonary shunt (body weight 15.2-54.2 kg). A spontaneous closure of the defect did not occurred in any of the patients, thus, transvenous closure of the defect was performed 2 to 10 weeks postoperatively. In the follow-up period of 4 to 22 months no complications such as thrombus formation, thromboembolic events or infections occurred. In low-cardiac-output syndrome refractory to all therapeutic measures mechanical circulatory support is the final method to keep the patient alive. In 11 children with refractory low-cardiac-output syndrome mechanical circulatory support was performed. In three of these, extracorporal membrane oxygenation (ECMO) was used, in eight children a ventricular assist device (Berlin Heart) was used.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Pressure↗

Heart transplantation in Berlin--1993 update.

Heart transplantation has become a routine procedure. Surgical techniques have been standardized and triple-drug immunosuppression has proven to be the most effective posttransplantation medical treatment. A shortage of donor organs has remained the major factor inhibiting extensive application of heart transplantation. Improved techniques of organ protection may eventually contribute to an extension of the donor pool. However, it seems to be more important to develop alternative procedures further (artificial heart, xenotransplantation, extended use of conservative surgical or medical treatment). The patient population undergoing heart transplantation will undoubtedly include more older, severely ill, polymorbid patients who are not suitable for alternative procedures. Pediatric heart transplantation may increase in the coming years and mechanical circulatory support will surely gain in importance for both adult and pediatric patients awaiting heart transplantation.

Adolescent↗

Use of polytetrafluoroethylene surgical membrane as a pericardial substitute in the correction of congenital heart defects.

Patients who undergo repair of congenital heart defects have a high probability of eventually needing a repeat operation. In such cases, use of a pericardial substitute can preclude adhesion formation, thereby helping to avert the complications of a repeat sternotomy. This report describes our use of the GORE-TEX polytetrafluoroethylene surgical membrane in 321 patients who underwent repair of congenital heart disease at our hospital between May of 1989 and December of 1992 (these cases account for 37.1% of all such repairs performed during this period). The patients' ages ranged from 2 days to 31 years (mean, 5.9 years). Eighty-eight patients (27.4%) had at least 1 previous median sternotomy, and 234 (73.0%) had a moderate to high probability of reoperation. Seventy-eight patients (24.3%) received a homograft, which was positioned extracardially in 63 cases. During a maximum follow-up period of 43 months (mean, 26 +/- 5.6 months), 11 patients died, for an overall mortality of 3.4%. In no case was death attributable to membrane-related complications. Postoperative complications were encountered in 12 patients (3.7%), 10 of whom required an early repeat thoracotomy. One patient had mediastinitis, for an incidence of 0.3% (in contrast to 0.2% in 864 patients who underwent similar repair without the use of a surgical membrane). No complications were encountered in the 27 patients in whom the membrane was implanted during delayed sternal closure. Seventeen patients (5.5% of the survivors) underwent a repeat sternotomy, for further correction of congenital heart defects, a mean of 20 months after the original repair. At reoperation, major complications were encountered. Although the number of reoperations was low, we conclude that use of the polytetrafluoroethylene surgical membrane for pericardial closure in children is a safe procedure that helps prevent complications at reoperation.

Adolescent↗

[Interventional high frequency perforation and enlargement of the outflow tract of pulmonary atresia].

In 18 patients with pulmonary atresia interventional perforation of the atresia was attempted using radiofrequency. All patients were referred for palliative surgery. The age ranged from 4 days to 19 years. After angiographic delineation of the relations between the right ventricular outflow tract and main pulmonary artery the tip of a radiofrequency perforation catheter (Cerablate-catheter, 2F, Osypka) was brought into contact with the atresia. The radiofrequency was applied in the unipolar fashion (radiofrequency-generator HAT 200, Osypka). Radiofrequency perforation was successfully performed in 14/18 patients, subsequent balloon dilatation was performed in 12 of these patients. In six patients with muscular atresia a Palmaz-stent was implanted into the right ventricular outflow tract. An inadvertent perforation of the right ventricular outflow tract occurred in three patients, of the pulmonary artery in two patients. However, these were tolerated without sequelae or clinical symptoms. The arterial oxygen saturation increased by 21%; in none of the patients was cardiac failure or pulmonary edema observed. Using the Cerablate-catheter even muscular atresias could be perforated. Implantation of a stent into the newly created right ventricular outflow tract results in a predictable communication between the right ventricle and the pulmonary artery. Although this interventional right ventricular outflow tract creation seems to be a promising new technique, experience is limited and there are no long-term results.

Adolescent↗